Unless I'm missing something in your description, why not data Container a = Single a | Many a a [a] Dan Günther Schmidt wrote:
Hi Jake,
Jake McArthur schrieb:
Günther Schmidt wrote:
data Container a = Single a | Many a [a] but the problem above is that the data structure would allow to construct a Many 5 [] :: Container Int. I think you meant to do either
data Container a = Single a | Many a (Container a)
nope, I pretty much meant what I wrote above, the solution here would mean deeply nested containers, since it's a recursive data structure.
I need a data structure as in my example without the [] being possible to be empty.
It's quite possible that in order to achieve this I would need to split this in 2 separate data declarations.
The idea behind this is that an "a" can "pocket" siblings, but only one level deep and that an "a's" list of "pocketed/swallowed" siblings must not be empty, because otherwise it would automatically be an "Single a".
Sorry, I really don't know how to put this better.
Günther
or
data Container a = Container a [a]
- Jake
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